The biggest new thing in American public education these days is a two-volume, 230-page, written-by-committee document called the Common Core State Standards.

Forty-five states have pledged to the federal government that they will adopt the standards — which specify the math and English skills that students must attain in each grade from kindergarten to the end of high school — within the next several years. Some of these states genuinely believe that doing so will make more of their students ready for college and careers. Others are on board primarily because the Obama administration has enticed them with billions of dollars from its Race to the Top competition, part of the administration’s economic-stimulus program.

Within the school-reform community, the standards have set off a virtual civil war. It pits those who believe that America desperately needs national standards to catch up to its international competitors against those who think that the administration, by imposing the standards on the states, is guilty of an unwise, or even illegal, power grab.

No matter how the debate over national standards plays out — and it may never be resolved — one undeniably positive development has resulted from all this. For the first time in almost half a century, education administrators and policymakers around the country are seriously discussing the role of a content-based curriculum in raising student achievement. And that means long-overdue recognition of the ideas of E. D. Hirsch, one of America’s greatest but also most neglected education reformers.

During the past quarter-century, Hirsch has warned over and over that something is dangerously amiss in the nation’s classrooms. His diagnosis could be summed up with the admonition: It’s the curriculum, stupid.

For the first 150 years of the republic, according to Hirsch, most schools followed a shared curriculum emphasizing the explicit content knowledge that children had to acquire in order to grow into literate adults and good citizens. As Hirsch writes in his most recent book, “The Making of Americans,” the country had “no official national curriculum, but it had the equivalent: a benign conspiracy among the writers of schoolbooks to ensure that all students would learn many of the same facts, myths, and values and so would grow to be competent, loyal Americans.” America’s public schools were the envy of the world during this period.

Starting in the 1930s, however, the progressive-education movement began a long march toward taking over the country’s teacher-training schools and professional teacher organizations. One of the progressives’ goals was undermining the idea of a prescribed curriculum, which they regarded as oppressive and out of sync with children’s natural learning styles.

This abandonment of a common curriculum by the schools, Hirsch argues, was largely responsible for the precipitous decline in student academic achievement that began in the 1960s. Academic stagnation set in, both absolutely and relative to achievement in the leading industrialized nations.

In four critically acclaimed books, beginning with the best-selling “Cultural Literacy” in 1985, Hirsch called for restoring a content-based, grade-by-grade curriculum in K–12 education. He also developed such a curriculum, called Core Knowledge, and created the Core Knowledge Foundation to help spread the word. Today, about 800 schools around the country use the curriculum. Many are charter schools, including the high-performing Carl Icahn School in the South Bronx.

Until recently, though, Hirsch was regarded as the odd man out in the school-reform movement. The Hirsch curriculum has never received anything like the massive amounts of money that philanthropic foundations have poured into structural education reforms, such as creating small high schools (a failed experiment, as the Gates Foundation itself conceded after spending $2 billion on them) or charter schools.

No school districts contracted with Hirsch’s organization to supply curricula or professional development for teachers — even as education officials wasted billions of dollars on inferior classroom materials purchased from the big commercial publishers. And it goes without saying that Hirsch’s ideas were anathema in the education schools, where the nation’s future teachers, instead of learning about the evidence supporting content knowledge in the classroom, are force-fed a toxic diet of radical political tracts by “education theorists” like Paulo Freire, William Ayers, and Jonathan Kozol. (Progressive-education doctrine holds that inculcating disadvantaged children in social-justice activism is just as important as teaching them the three Rs.) But now that most of the country has signed up for the Common Core standards, Hirsch’s Core Knowledge curriculum has suddenly become highly relevant to the national education debate. School leaders from several states are now knocking on Hirsch’s door, looking for help in implementing the standards.

I once assumed that the least likely place for Hirsch’s ideas to gain traction was New York City — the nation’s largest school district, with more than 1 million students and 1,700 schools.

After Mayor Michael Bloomberg and his handpicked schools chancellor, Joel Klein, assumed control of Gotham’s public schools in 2002, they won their reputation as education reformers by expanding charter schools, closing failing schools, and introducing accountability schemes linking teacher and principal evaluations to student test scores. Curriculum was an afterthought.

The default reading program for most elementary schools was “balanced literacy,” an approach developed by Teachers College professor Lucy Calkins. Her organization received almost $50 million in city contracts to provide a reading and writing program that disdained content knowledge and any prescribed curriculum. Calkins’ “child-centered” instructional model is based on the Romantic philosophy that all children are natural readers and writers. In the proper classroom environment and with a mere helping hand from teachers, they can supposedly be inspired to find their individual paths to literacy.

In a typical balanced-literacy classroom, phonics and decoding skills are taught only episodically. Beginning readers try to intuit the meaning of words through context clues in the text. One of Calkins’ innovations is the “writer’s workshop,” in which first- and second-graders write first drafts without any attention to sentence structure, paragraphing, grammar, or spelling. The students then edit one another’s drafts until a “publishable” work emerges.

The teacher’s role in this process is mostly advisory; as the progressive-education credo puts it, she must be “a guide on the side, rather than a sage on the stage.” This is the antithesis of the explicit teaching of phonics and academic content required in Hirsch’s early-childhood reading curriculum. As Hirsch might have predicted, the city’s reading scores on the gold-standard federal NAEP tests largely remained flat from 2003 through 2011.

More than halfway through his tenure, however, Klein did something extremely unusual for an ambitious education official. He was curious enough to read Hirsch’s books, he considered the evidence, and he began to have second thoughts about the instructional approach that his own administration was invested in and still publicly defending against a handful of critics (myself included).

Klein was particularly impressed by Hirsch’s third book, “The Knowledge Deficit,” which came out in 2006 and summarized the consensus in cognitive-science research that children, to improve their reading comprehension, must acquire extensive background knowledge.

In fact, Hirsch has proposed as a fundamental law of language that “prior relevant knowledge” is essential to building reading comprehension, particularly in the early grades. Thus, the Core Knowledge curriculum requires that teachers spend as much time on content knowledge in history, geography, and science as on the actual mechanics of reading. And Hirsch has emphasized that building this background knowledge is even more important for disadvantaged minority children, who begin school far behind their middle-class peers in vocabulary and general knowledge of the world.

Klein exchanged e-mails with Hirsch about “The Knowledge Deficit” and, in the fall of 2007, invited Hirsch and Core Knowledge Foundation President Linda Bevilacqua to the Department of Education’s headquarters for a series of private meetings. Klein told his visitors that until he read Hirsch’s book, he hadn’t found anyone who could satisfactorily explain why the city’s NAEP reading scores were so disappointing, particularly in the eighth grade. Bevilacqua briefed DOE officials, explaining the theory and research behind the Hirsch literacy program.

Out of these meetings came an agreement between Klein and Hirsch to set up a three-year experiment. Beginning in September 2008, 10 city elementary schools would use Hirsch’s early-childhood literacy program. These Core Knowledge schools would be matched with 10 demographically similar schools using “balanced literacy,” allowing the Department of Education to compare the two approaches. At the DOE, the Hirsch pilot program became known as “Joel’s pet project.”

On September 22, 2009, Klein called a press conference at PS 30, one of the Core Knowledge schools in the South Bronx, to announce the results of the experiment’s first year. With Hirsch at his side, Klein presented data showing that students in the schools using the Hirsch curriculum had made gains in reading five times greater than those in the comparison schools.

“The results we’re announcing today represent an early but promising indication of Core Knowledge’s effectiveness,” Klein said. “Teachers and principals have been very happy with the program, and the participating students have made important progress toward becoming skillful readers.”

The new Common Core standards are creating a historic opportunity to introduce Hirsch’s curriculum to many more schools and classrooms. Written by a consortium representing the National Governors Association and the Council of Chief State School Officers, the standards themselves make clear that they do not constitute a curriculum; they merely state what children should know at the end of each grade level and the skills that they must acquire to stay on course toward college or career readiness.

Each school system still needs to find a curriculum — that is, the particular academic content taught by teachers from lesson to lesson and from grade to grade — that will help its students achieve the standards.

As the standards document for English Language Arts puts it: “While the Standards make references to some particular forms of content, including mythology, foundational US documents, and Shakespeare, they do not — indeed, cannot — enumerate all or even most of the content that students should learn. The Standards must therefore be complemented by a well-developed, content-rich curriculum consistent with the expectations laid out in this document.”

State and local school officials serious about adhering to these guidelines can’t help noticing that Hirsch’s Core Knowledge is a “well-developed, content-rich curriculum” that it is already aligned with the Common Core standards and that it has been successfully field-tested.

New York — which was one of the first states to sign up for the standards and which has received hundreds of millions of dollars for its implementation from the Race to the Top fund — has already taken notice. This past April, the state’s education department announced that Core Knowledge had won a $5 million contract to produce pre-K-through-second-grade curricular materials aligned to the standards.

And last month the New York City Department of Education announced that Core Knowledge would now become a recommended reading curriculum for grades K-2 and that Lucy Calkins’ balanced literacy was removed from the recommended list.

The Common Core train has left the station, but we don’t know yet whether that train will follow a route that leads to a restored American curriculum and a nation of literate and knowledgeable adults. Whatever differences they might have on other issues, school reformers of all stripes should monitor and comment on the standards’ implementation in the coming years. Reformers could help ensure that the curricula that state and local school-district officials select meet the Common Core’s own benchmark of “rich content knowledge.”

Sol Stern is a contributing editor of City Journal, where this essay first appeared.